#include <LiquidCrystal.h>

const int trig_pin = 2;
const int echo_pin = 3;

long distance, duration;

const int rs = 5, en = 4, d4 = 9, d5 = 8, d6 = 7, d7 = 6;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

void setup() 
{
  lcd.begin(16, 2);
  lcd.setCursor(0, 0);
  pinMode(trig_pin, OUTPUT);
  pinMode(echo_pin, INPUT);
}

void loop() 
{
digitalWrite(trig_pin,HIGH);
delayMicroseconds(20);
digitalWrite(trig_pin,LOW);
delayMicroseconds(20);

duration = pulseIn(echo_pin, HIGH); 
distance= duration*0.034/2;

lcd.setCursor(0,1); 
lcd.print(distance);
lcd.print("cm   ");
delay(100);
}